Contaminación de los cereales y los derivados de cereales por micotoxinas en Rumania

Mycotoxins are among the most frequent contaminants of wheat and wheat-based products. The most important mycotoxins in wheat are mainly Fusarium toxins, such as deoxynivalenol (DON), zearalenone (ZEA), nivalenol, HT-2 toxin (HT-2), T-2 toxin, and, recently studied, the emerging mycotoxins, particularly enniatins (ENs) and beauvericin. Agriculture and especially wheat cultivation are important parts of the Romanian economy. Despite its high producer and consumer potential, only sporadic data concerning mycotoxin presence in wheat foodstuffs in Romania is registered. The aim of this thesis was to survey the natural presence of both regulated and unregulated Fusarium mycotoxins in wheat and wheat-based products from Romania, the research being divided into four blocks: validation of analytical methods; surveillance of natural occurrence of Fusarium mycotoxins in wheat and wheat-based products from Romania; influence of various factors on mycotoxin production; risk assessment studies for the Romanian population. In this thesis, different multi-component qualitative and quantitative analytical methods have been validated in order to investigate the occurrence of various Fusarium mycotoxins, including old discovered mycotoxins, but also emerging mycotoxins, in wheat and wheat-based food commodities. Sample preparation consisted particularly in solid-liquid extractions, presenting the advantage of being rapid, and user-friendly. Analysis methods were different depending on the mycotoxins evaluated, liquid or gas chromatography coupled to tandem mass spectrometry, both presenting satisfactory results for linearity, sensitivity, accuracy, matrix effect and repeatability. Concerning natural mycotoxin occurrence in Romanian wheat and wheat-based products, DON and ENs showed the highest frequencies. With respect to the legislated mycotoxins, DON was the most detected in Romanian wheat (60/102, 59%), and wheat-based products (114/181, 63%). The highest frequency of DON was observed for pasta (34/40, 85%), whereas the highest levels of DON (mean value of 353 μg kg−1) were found for wheat flour. From the emerging mycotoxins, ENB was the most prevalent in both wheat samples (55/133, 41%), and wheat-based products (35/111, 32%). With respect to the correlation between Fusarium mycotoxin levels in Romanian wheat and weather conditions during the grain-growing season, a complex 2-year survey was presented. For the emerging mycotoxins, after monitoring three different counties, using univariate data analysis and multivariate approach, the results indicated that high precipitation (with at least 20 mm more than long-term normal monthly precipitation) during the months of May and July promote high moisture in wheat kernels, increasing EN occurrence, co-occurrence and mean concentrations, particularly ENA1, ENB, and ENB1. Regarding the other Fusarium mycotoxins, the results suggested that a prolonged rainy weather during earing phase, anthesis, dough formation and filling (months of May and June) influence fungi development and mycotoxin production, particularly DON, HT-2 and ZEA. Comparing the occurrence data on emerging mycotoxins in Romanian organic and conventional wheat, higher values for incidences, mean levels, and number of mycotoxins found simultaneously were registered for organic wheat samples, but, interestingly, the maximum values found corresponded to conventional wheat samples. Concerning the influence of the wheat cultivar on emerging mycotoxin presence, the highest means and levels were for Arieşan, Balaton, and Izvor varieties. Finnaly, the estimated daily intake (EDI) of Fusarium mycotoxins through wheat-based product consumption by the Romanian adult population was calculated. The highest EDI values were registered for the sum of DON, 3AcDON and 15 AcDON (689.6 ng kg-1 bw day-1 at an overestimation), even so being lower than the tolerable daily intake established by the European regulations.